Communication device, control method, and program

Abstract

To provide a mechanism to prevent or reduce a decrease in fairness between data communications due to interrupts.SOLUTION: A communication device performs communication in accordance with the IEEE 802.11 standard series. The communication device communicates a first PPDU (Physical layer (PHY) Protocol Data Unit) to a first other communication device during a period in which the communication device has a transmission opportunity (TXOP) for transmitting a PPDU. When a second other communication device transmits a second PPDU during the period, the communication device notifies the second other communication device of an upper limit value of the transmission opportunity for transmitting the second PPDU.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a communication device, a control method, and a program. [Background technology]

[0002] With the recent increase in data traffic, development of communication technologies such as wireless local area networks (WLANs) is progressing. The IEEE (Institute of Electrical and Electronics Engineers) 802.11 series of standards is known as the main WLAN communication standard. The IEEE 802.11 series includes IEEE 802.11a / b / g / n / ac / ax / be. To further improve communication reliability, the IEEE 802.11bn standard is being developed as the successor to the IEEE 802.11be standard. The IEEE 802.11 Working Group (WG), which is formulating the IEEE 802.11bn standard, is defining the goals and scope of the standard in the UHR SG, and the TGbn will specify the detailed technical content to be included in the standard. UHR SG stands for Ultra High Reliability Study Group. TGbn is also an abbreviation for Task Group bn. The name UHR was chosen for convenience, reflecting the goals and key features of the successor standard, and may be replaced by a different name once the standard is fully developed. Similarly, the name IEEE 802.11bn may be replaced by a different name once the standard is fully developed. However, this specification and the accompanying claims are essentially applicable to all successor standards to the 802.11be standard.

[0003] One of the candidate technologies included in the IEEE802.11bn standard is a communication format called preemption, which enables communication of data categorized as low-latency data. Preemption is a technology that interrupts non-low-latency data communication when low-latency data arrives while non-low-latency data is being transmitted, and is expected to improve latency performance compared to existing standards. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-50133 Summary of the Invention [Problem to be solved by the invention]

[0005] As such, IEEE802.11bn is considering a standard for preemption communication to improve latency characteristics. However, when a large amount of data (e.g., low-latency data) that should be preempted is generated, the communication performance of other data (e.g., non-low-latency data) may be significantly impaired. In this case, fairness between these data may become an issue.

[0006] The present invention has been made in consideration of at least one of the above-mentioned problems, and an object of one aspect of the present invention is to provide a mechanism for preventing or reducing a decrease in fairness between data communications due to interrupts. [Means for solving the problem]

[0007] A communication device according to one aspect of the present invention is a communication device that communicates in accordance with the IEEE802.11 standard series, and is characterized by comprising: a communication means for communicating a first PPDU (Physical layer (PHY) Protocol Data Unit) with a first other communication device during a period in which the communication device has a transmission opportunity (TXOP) for transmitting the PPDU; and a notification means for notifying an upper limit value of a transmission opportunity for transmitting the second PPDU when a second other communication device transmits a second PPDU during the period. [Effects of the Invention]

[0008] According to one aspect of the present invention, it is possible to provide a mechanism for preventing or reducing a decrease in fairness between data communications due to interrupts. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a wireless communication system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of the functional configuration of a communication device according to the present embodiment. [Figure 3] FIG. 2 is a diagram showing the hardware configuration of a communication device according to the embodiment. [Figure 4] FIG. 3 is a sequence diagram showing communication processing executed in the first embodiment. [Figure 5] FIG. 3 is a diagram showing an example of the format of a control frame used to notify a preemption communication time upper limit value in the first embodiment. [Figure 6] FIG. 3 is a diagram showing an example of a format of a PPDU used to notify a preemption communication time upper limit value in the first embodiment. [Figure 7] FIG. 4 is a flowchart showing processing executed by the AP 102 in the first embodiment. [Figure 8] FIG. 4 is a flowchart showing processing executed by the STA 104 in the first embodiment. [Figure 9]FIG. 10 is a sequence diagram showing communication processing executed in the second embodiment. [Figure 10] FIG. 10 is a diagram showing an example of a frame format used to notify a preemption communication time upper limit value in the second embodiment. [Figure 11] FIG. 10 is a flowchart showing processing executed by the AP 102 in the second embodiment. [Figure 12] FIG. 10 is a flowchart showing processing executed by the STA 103 in the second embodiment. [Figure 13] FIG. 11 is a sequence diagram showing communication processing executed in the third embodiment. [Figure 14] FIG. 11 is a diagram showing an example of the format of a first portion used to notify a preemption communication time upper limit value in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the claimed invention. Although the embodiments describe multiple features, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined in any desired manner.

[0011] (Network configuration) Fig. 1 shows an example of the configuration of a network according to this embodiment. Fig. 1 shows a configuration including one AP 102 and two STAs 103 and 104 as communication devices that perform wireless LAN communication in accordance with the IEEE802.11bn standard. As shown in Fig. 1, the network formed by the AP 102 is indicated by a circle 101. The STAs 103 and 104 can transmit and receive signals transmitted and received by the AP 102.

[0012] Note that this diagram is merely an example, and other communication devices performing wireless LAN communication may exist in a wider area. These communication devices may perform wireless LAN communication in accordance with the IEEE 802.11be standard. Alternatively, they may be so-called legacy devices that do not comply with the IEEE 802.11bn standard but only comply with the IEEE 802.11a / b / g / n / ac / ax / be standards.

[0013] The AP 102 and the STAs 103 and 104 may also be configured to support wireless communication based on other communication standards such as Bluetooth (registered trademark), NFC, Bluetooth (registered trademark) LE (Low Energy), etc. NFC stands for Near Field Communication.

[0014] The AP 102 and the STAs 103 and 104 can also be configured to support wired communication using an Ethernet cable or wired communication using optical fiber. The AP 102 and the STAs 103 and 104 can also be configured to support cellular wireless communication such as 5G or LTE (Long Term Evolution).

[0015] Specific examples of the AP 102 include, but are not limited to, a wireless LAN router and a personal computer (PC). The AP 102 and the STAs 103 and 104 may also be information processing devices such as wireless chips that support the transmission and reception of PPDUs. In this case, the wireless chips may be configured to perform various controls using internal hardware circuits. Various processes may also be performed by a processor, such as an ASIP, internal hardware circuits, and memory working together. ASIP stands for Application-Specific Instruction Set Processor.

[0016] Specific examples of the STAs 103 and 104 include, but are not limited to, cameras, tablets, smartphones, PCs, mobile phones, video cameras, smart glasses, and wearable devices such as HMDs (head-mounted displays).

[0017] In the following description, the AP 102 and the STAs 103 and 104 will be used as examples.

[0018] (AP and STA configuration) FIG. 2 is a block diagram showing the functional configuration of the AP 102 and the STAs 103 and 104.

[0019] Here, the AP 102 and the STAs 103 and 104 have a wireless LAN control unit 201 , a wireless frame generation unit 202 , a wireless frame processing unit 203 , a UI control unit 204 and a storage control unit 205 .

[0020] The wireless LAN control unit 201 includes an antenna and circuit for transmitting and receiving wireless signals to and from other communication devices, and a program for controlling them. The wireless LAN control unit 201 controls wireless LAN communications based on frames generated by the frame generation unit in accordance with the IEEE802.11 standard series.

[0021] The wireless frame generation unit 202 generates frames to be transmitted by the wireless LAN control unit 201 .

[0022] The wireless frame processing unit 203 processes frames received from other communication devices.

[0023] The UI control unit 204 includes hardware related to the user interface, such as a touch panel or buttons, for accepting operations on the AP by a user who uses the AP, and programs for controlling these. The UI control unit 204 also has a function for presenting information to the user, such as displaying images or outputting audio. The memory control unit 205 controls writing and reading of data to and from memory units, such as ROM and RAM, that store programs and data running on the AP.

[0024] 3 shows the hardware configuration of the AP 102 and the STAs 103 and 104 according to this embodiment. The AP and the STAs each include, as an example of their hardware configuration, a storage unit 301, a control unit 302, a function unit 303, an input unit 304, an output unit 305, a communication unit 306, and a wireless antenna 307.

[0025] The storage unit 301 is configured with one or more memories such as ROM and / or RAM, and stores programs for performing various operations described below and various information such as communication parameters for wireless communication. Note that in addition to memories such as ROM and RAM, the storage unit 301 may also use storage media such as a flexible disk, hard disk, SSD, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, non-volatile memory card, and DVD. SSD is an abbreviation for Solid State Drive.

[0026] The control unit 302 is configured by, for example, one or more processors such as a CPU or MPU, an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), etc. Here, CPU is an acronym for Central Processing Unit, and MPU is an acronym for Micro Processing Unit. The control unit 302 controls the entire device by executing programs stored in the storage unit 301.

[0027] The control unit 302 may control the device in cooperation with an OS (Operating System) and a program stored in the storage unit 301. The control unit 302 also controls the function unit 303 to perform predetermined processes such as imaging, printing, and projection.

[0028] The functional unit 303 is hardware that enables the AP or STA to execute predetermined processing. For example, if the AP or STA is a camera, the functional unit 303 is an imaging unit that performs imaging processing. Also, for example, if the AP or STA is a printer, the functional unit 303 is a printing unit that performs printing processing. Also, for example, if the AP or STA is a projector, the functional unit 303 is a projection unit that performs projection processing. The data processed by the functional unit 303 may be data stored in the storage unit 301, or may be data communicated with another communication device via the communication unit 306, which will be described later.

[0029] The input unit 304 receives various operations from the user. The output unit 305 outputs various types of information to the user. Here, the output by the output unit 305 includes at least one of display on a screen, audio output by a speaker, vibration output, and the like. Note that both the input unit 304 and the output unit 305 may be implemented by a single module, such as a touch panel. Furthermore, the input unit 304 and the output unit 305 may be integrated with the AP or STA, respectively, or may be separate units.

[0030] The communication unit 306 includes a so-called wireless LAN chip and controls wireless communication compliant with the IEEE802.11 standard series and IP communication. In this embodiment, the communication unit 306 can execute processing compliant with at least the IEEE802.11bn standard.

[0031] The communication unit 306 is a processing device that generates UHR PPDUs (Physical layer (PHY) Protocol Data Units) defined in the IEEE 802.11bn standard. However, the communication unit 306 may also have a function to generate PPDUs of a type defined in a standard earlier than the IEEE 802.11bn standard.

[0032] Furthermore, the communication unit 306 controls the wireless antenna 307 to transmit and receive wireless signals for wireless communication. The AP and STA communicate content such as image data, document data, and video data with other communication devices via the communication unit 306.

[0033] The wireless antenna 307 may be physically configured with two or more antennas to realize MIMO (Multi-Input and Multi-Output) transmission and reception. The wireless antenna 307 may be configured as a separate unit from the communication unit 306, or may be configured as a single module together with the communication unit 306. The wireless antenna 307 is an antenna capable of communication in the 2.4 GHz band, 5 GHz band, 6 GHz band, 45 GHz band, and 60 GHz band.

[0034] Although the communication device in Fig. 3 has one antenna, the communication device may have two or more antennas. Alternatively, the communication device may have a different antenna for each frequency band. In the example of Fig. 3, the communication device is configured to have only one communication unit 306, but it may also be configured to have a separate communication unit for each of multiple wireless antennas.

[0035] AP102 may be any communication device having the configuration of Figures 2 and 3, and may be a so-called AP-dedicated communication device such as a wireless LAN router, or may be a communication device with AP functions such as a smartphone, camera, or printer.

[0036] (Processing flow) Next, several embodiments will be described, including the flow of the processes executed by the AP and STA as described above, and sequences in a wireless communication system. First Embodiment FIG. 4 is a sequence diagram showing an example of a process in which the STA 104 transmits a preemption signal to the AP 102 while the AP 102 is transmitting to the STA 103. In FIG.

[0037] In this embodiment, the AP 102 acquires a TXOP to transmit a PPDU to the STA 103. In this TXOP, the AP 102 permits preemption communication to all connected STAs that support preemption communication. The AP 102 divides the PPDU to be transmitted to the STA 103 into an appropriate number of PPDUs and transmits the divided PPDUs multiple times.

[0038] AP102 transmits an RTS (Request-To-Send) frame 401 to STA103. Upon receiving the RTS frame 401, STA103 transmits a CTS (Clear-To-Send) frame 402 to AP102. A non-preemption-capable STA (not shown) that receives the CTS frame 402 enters a NAV (Network Allocation Vector: transmission prohibition time) and is unable to transmit during AP102's transmission time. Preemption-capable STA104 does not enter the NAV. AP102 transmits a PPDU 403 to STA103, and STA103 transmits a BlockAck frame 404, which is a signal acknowledging receipt of PPDU 403, to AP102. AP102 then transmits a PPDU 405 to STA103, and upon receiving PPDU 405, STA103 transmits a BlockAck frame 406 to AP102. The transmission of PPDU 405 is the second transmission of the divided PPDU, and if there is no preemption communication, the PPDU transmission from AP 102 to STA 103 and the BlockAck transmission from STA 103 to AP 102 are repeated the number of times equal to the number of PPDU divisions.

[0039] In this embodiment, the STA 104 receives low-latency data while the AP 102 is transmitting the PPDU 405. The STA 104 transmits the received low-latency data to the AP 102 by preemption communication, and then transmits a Preemption Request 407 to the AP 102 after transmitting a BlockAck frame 406. The AP 102 receives the Preemption Request frame 407 and transmits a Preemption Response frame 408 to the STA 104 to notify it of permission for preemption communication and the upper limit of the transmission PPDU time.

[0040] The upper limit of the transmission PPDU time can be determined by the AP 102 before acquiring the TXOP, depending on the specifications and settings of the AP 102 or the communication conditions of the AP itself and surrounding terminals. The determination can be made after acquiring the TXOP, or it can be changed as appropriate during the process.

[0041] Upon receiving the preemption response frame, STA 104 transmits a PPDU 409 to AP 102 based on the preemption information contained in the frame. AP 102 transmits a BlockAck frame 410 to STA 104, ending the preemption communication, and resumes transmitting a PPDU 411 to STA 103. STA 103 transmits a BlockAck frame 412 in response to PPDU 411 to AP 102, after which STA 104 can again perform preemption communication.

[0042] The frame formats of the preemption request frame 407 and the preemption response frame 408 are shown in FIG. 5(A) and FIG. 5(B), respectively.

[0043] The format of the Preemption Request frame is made up of a Frame control field 501, a Duration / ID field 502, an RA field 503, a TA field 504, and an FCS field 505. The Frame control field 501 has, from the beginning, a Protocol Version subfield 506, a Type subfield 507, and a Subtype subfield 508.

[0044] The format of the preemption response frame includes a Frame control field 509 and a Duration / ID field 510. This format also includes an RA field 511, a Preemption allowance field 512, a Preemption limit field 513, and an FCS field 514. The Frame control field 509 is the same as the Frame control field 501 included in the preemption request frame. That is, the Frame control field 509 includes a Protocol Version subfield 506, a Type subfield 507, and a Subtype subfield 508.

[0045] The type of the frame is indicated by the values ​​of the Type subfield 507 and the Subtype subfield 508. Table 1 shows the relationship between the values ​​and the types.

[0046] [Table 1] A value of 01 in the Type subfield indicates that both the preemption request frame and the preemption response frame are Frame Control. The Subtype subfield contains a value that indicates the frame type, but the values ​​shown in Table 1 are merely examples and other values ​​may be used. Also, although the frame type is expressed by a combination of the Type subfield and the Subtype subfield in Table 1, it may be expressed by using other subfields as appropriate.

[0047] The preemption allowance field 512 included in the preemption response frame is a 1-bit field as follows: That is, it is a 1-bit field indicating whether or not the AP 102 grants preemption to the STA 104 that has transmitted the preemption request frame.

[0048] The Preemption limit field 513 is a field that indicates the upper limit of the time length of a single PPDU that the STA 104 transmits in preemption communication. For example, it can be set to a 15-bit field that can indicate a value from 0 to 65,535 microseconds. The number of bits may be other than 15, and the value may not be in units of 1 microsecond. Alternatively, the upper limit of the time length of the PPDU may be determined from the value of the Preemption limit field according to a predetermined table.

[0049] The Preemption Limit field 513 may be an upper limit value for the total duration of a single PPDU transmitted by the STA 104 with preemption in the TXOP. In other words, if preemption communication is performed multiple times in the TXOP, a frame exchange of a Preemption Request frame and a Preemption Response frame occurs between the AP 102 and the STA 104 for each communication. However, the value included in the Preemption Limit field 513 indicated by the Preemption Response frame may be a value obtained by subtracting the duration of the PPDUs already transmitted with preemption. The Preemption Limit field 513 may also be an upper limit value indicating the number of PPDUs transmitted by the STA 104 with preemption in the TXOP. For example, storing 0 in this field may indicate that the STA 104 may transmit only a single SU PPDU in the TXOP. Additionally, it may indicate that the STA 104 may transmit only a single MU PPDU and a single TB PPDU in the TXOP. Note that SU PPDU stands for Single-User PPDU, MU PPDU stands for Multi-User PPDU, and TB PPDU stands for Trigger-based PPDU.

[0050] In addition to the above-described configuration, the upper limit value of the preemption communication time may be included in the PPDU 405 transmitted by the AP 102 to the STA 103. The frame format of the PPDU in this case is shown in FIG.

[0051] The PPDU includes a Frame control field 601, a Duration / ID field 602, an Address 1 field 603, an Address 2 field 604, and an Address 3 field 605. The PPDU also includes a Sequence Control field 606, an Address 4 field 607, and a QoS Control field 608. The PPDU also includes an A-Control field 609, a Frame body field 610, and an FCS field 611. The Type subfield and Subtype subfield included in the Frame control field 601 are Type=10 and Subtype=0000, respectively, which indicate that this frame is a PPDU. The A-Control field 609 is made up of a Control list subfield 612 and a Padding field 613. The Control list subfield 612 is made up of a combination of a Control ID subfield 614 and a Control information subfield 615.

[0052] The Control list subfield with Control ID=10 is defined as the Preemption Control subfield. The Control ID may be any other value as long as it is a reserved value in existing standards. The Control information subfield 615 consists of a Preemption allowance subfield 616 and a Preemption limit subfield 617. Both subfields store the same information as the subfields of the same name contained in the Preemption response frame in Figure 5. However, the IEEE 802.11 standard stipulates that the A-Control field 609 is 30 bits and the Control ID subfield 614 is 4 bits. For this reason, the combined length of the Preemption allowance subfield 616 and the Preemption limit subfield 617 must be 26 bits or less.

[0053] FIG. 7 is a flowchart illustrating the operation of the AP 102 in this embodiment.

[0054] After the AP 102 acquires the TXOP, it divides the PPDU to be transmitted to the STA 103 into N pieces (S701).

[0055] N is an integer of 2 or more and is a predetermined value.

[0056] The station 102 transmits an RTS frame to the station 103 (S702) and receives a CTS frame transmitted from the station 103 (S703).

[0057] Thereafter, the STA 103 transmits a PPDU to the STA 103 (S704), and receives a BlockAck frame (denoted as "BA" in FIG. 7) transmitted by the STA 103 (S705).

[0058] It is determined whether a Preemption Request frame is received within a certain time period after receiving the BlockAck frame (S706), and if a Preemption Request frame is received, the process proceeds to S707. In S707, the AP 102 transmits a Preemption response frame to the STA 104 in response to the Preemption request frame.

[0059] Thereafter, the AP 102 receives the PPDU transmitted by the STA 104 in the preemption communication (S708), and transmits a BlockAck frame including information on whether the received PPDU was received or not (S709) to the STA 104. When S709 ends, the process returns to S706.

[0060] If a preemption request frame is not received in S706, the process proceeds to S710. If the transmitted PPDU is the Nth one, the process proceeds to S711. If the transmission inhibition period (NAV) has ended, the sequence ends.

[0061] If it is determined in step S711 that the transmission inhibition period (NAV) has not ended, the process proceeds to step S706, where the reception of a preemption request frame is waited for a certain period of time.

[0062] If the PPDU transmitted in S710 is not the Nth PPDU, the process proceeds to S702 to transmit the next PPDU.

[0063] FIG. 8 is a flowchart illustrating the operation of the STA 104 in this embodiment.

[0064] First, the STA 103 receives an RTS frame transmitted to another STA belonging to the BSS to which the STA 103 belongs and a CTS frame transmitted to the AP by the STA to which the RTS frame is to be transmitted, and acquires the transmission inhibition period (NAV) (S801).

[0065] It is determined whether the transmission prohibition time has ended (S802), and if so, this sequence ends.

[0066] If the transmission prohibition time has not expired, it is determined whether low-latency data to be transmitted by preemption communication exists in the transmission buffer of the STA 104 (S803). If low-latency data does not exist in the transmission buffer of the STA 104, the process returns to S802.

[0067] If low-latency data exists, the process proceeds to S804, and if frame transmission is not performed for a certain period of time, the process proceeds to S805.

[0068] In S805, a preemption request frame is transmitted to the AP 102.

[0069] The preemption response frame is received from the AP 102, and the values ​​of the preemption allowance field and the preemption limit field are acquired (S806). The calculated upper limit of the preemption transmission time is denoted as L_prlim.

[0070] If the preemption allowance field has a value that allows preemption communication (S807), the process proceeds to S808.

[0071] The PPDU length (denoted as L_ppdu) to be transmitted to the AP 102 is determined so as to be equal to or less than L_prlim (S808).

[0072] The PPDU is preemptively transmitted to the AP 102 (S809), and a BlockAck frame is received from the AP 102 (S810).

[0073] Then, the process proceeds to S802. If the low latency data does not exist in the transmission buffer of the STA 104 in S803, the process proceeds to S802.

[0074] If preemption is not permitted in S807, the process proceeds to S811, where the process waits until the transmission prohibition time has ended, and when the transmission prohibition time has ended, the process ends.

[0075] In the example shown in FIG. 8, if preemption is not permitted in S807, the process proceeds to S811, but may also return to S802.

[0076] 8, the process returns to S802 after S810. However, if the PPDU length required to transmit low-latency data in preemption communication is longer than L_prlim, the process may proceed as follows. That is, the process returns to S802, but if the transmission prohibition time has not expired in S802, S803 may be skipped. If frame transmission is not performed for a certain period of time in S804, S805 to S807 may be skipped and the process may proceed to S808.

[0077] According to the first embodiment described above, when a PPDU of low latency data is transmitted from the STA 104 to the AP 102 by interrupt during a transmission prohibition time, the transmission time of the low latency data can be limited so as not to exceed the upper limit value (L_prlim). This ensures a certain level of fairness between communications of low latency data and non-low latency data.

[0078] In the first embodiment, a case where a PPDU of low-latency data is transmitted from the STA 104 to the AP 102 by interrupt during a transmission prohibition time has been mainly described, but the present invention is not limited to this. That is, the first embodiment is also applicable to a case where a PPDU of low-latency data is transmitted from the AP 102 to the STA 104 by interrupt during a transmission prohibition time. In this case, the STA 103 may acquire a TXOP to transmit a PPDU to the AP 102, and may notify the AP 102 of a preemption communication time upper limit value. At this time, the preemption communication time upper limit value may be included in a PPDU (not shown) transmitted from the STA 103 to the AP 102. In this case, the frame format of the PPDU may be as shown in FIG. 6.

[0079] <Second embodiment> FIG. 9 is a sequence diagram showing an example of a process in which the AP 102 transmits a PPDU to the STA 104 in preemption communication while the STA 103 that has acquired the TXOP is transmitting to the AP 102.

[0080] In this embodiment, the STA 103 acquires a TXOP to transmit a PPDU to the AP 102. In this TXOP, the STA 103 grants preemption communication to all STAs connected to the AP that supports preemption communication. The STA 103 divides the PPDU to be transmitted to the AP 102 into an appropriate number of PPDUs and transmits the divided PPDUs multiple times.

[0081] After acquiring the TXOP, the STA 103 transmits a Preemption Report frame 901 to all STAs that belong to the same BSS as the connected AP.

[0082] FIG. 10 shows the frame format of the preemption report frame 901.

[0083] The preemption report frame includes a frame control field 1001, a duration / ID field 1002, an RA field 1003, and a TA field 1004. The preemption report frame also includes a BSSID field 1005, a preemption allowance field 1006, a preemption limit field 1007, and an FCS field 1008.

[0084] The configuration of Frame control field 1001 is the same as that shown in the first embodiment, and the Type subfield and Subtype subfield included therein specify the type of frame. In this embodiment, when the value of the Type subfield is 01 and the value of the Subtype subfield is 0010, it indicates that the frame is a Preemption report frame. However, even if the above values ​​are different, it is sufficient as long as it indicates that the frame is a Preemption report frame.

[0085] The AP and STA that received this frame determine from the BSSID field 1005 whether the frame was sent to the BSS to which the own terminal belongs.

[0086] If the value of the BSSID field 1005 matches the BSS to which the terminal belongs, information on whether preemption communication is permitted is obtained from the value of the Preemption allowance field 1006. Also, information on the upper limit of preemption communication is obtained from the Preemption limit field 1007.

[0087] The Preemption limit field indicates the upper limit of the total preemption communication time allowed to the AP and STA in the TXOP. For example, it can be set as a 15-bit field that can indicate a range from 0 to 65,535 microseconds. The number of bits may be other than 15, and the unit may not be 1 microsecond. A method may be used in which the upper limit of the PPDU time length is determined from the value of the Preemption limit field according to a predetermined table.

[0088] The Preemption Limit field may be an upper limit value for the total duration of a single PPDU transmitted by the AP 102 with preemption in the TXOP. In other words, if preemption communication is performed multiple times in the TXOP, frame exchange occurs multiple times between the AP 102 and the STA 104. In other words, a frame exchange of a preemption request frame and a preemption response frame occurs between the AP 102 and the STA 104 for each preemption communication. In this case, the value included in the Preemption Limit field indicated by the Preemption Response frame may be a value obtained by subtracting the duration of the PPDUs already transmitted with preemption. Alternatively, the Preemption Limit field may be an upper limit value indicating the number of PPDUs transmitted by the STA 104 with preemption in the TXOP. For example, storing 0 in this field may indicate that the STA 104 may transmit only a single SU PPDU in the TXOP. Additionally, it may indicate that the STA 104 may transmit only a single MU PPDU and a single TB PPDU in the TXOP. Note that SU PPDU stands for Single-User PPDU, MU PPDU stands for Multi-User PPDU, and TB PPDU stands for Trigger-based PPDU.

[0089] In this embodiment, preemption is performed during the NAV period set by the STA 103. However, the upper limit of the total preemption communication time permitted for each of the AP and STA in the NAV may be equal to the product of the NAV time length and the value in the Preemption limit field. Alternatively, instead of the upper limit of the total preemption communication time, the upper limit of the total time length of a single PPDU to be transmitted may be considered. In either case, the value of the Preemption limit field is between 0 and 1. For example, when the field is configured with 7 bits, the value obtained by multiplying the decimal representation of the Preemption limit field by 1 / 128 is the Preemption limit.

[0090] The AP and STA that have received the preemption report frame 901 acquire preemption permission information and a preemption upper limit value, which are information about preemption communication included in the frame.

[0091] The STA 103 transmits an RTS frame 902 to the AP 102 , and the AP 102 transmits a CTS frame to the STA 103 as a response signal to the RTS frame 902 .

[0092] Thereafter, the STA 103 transmits a PPDU 904 to the AP 102, and upon receiving the PPDU 904, the AP 102 transmits a BlockAck frame 905 including PPDU reception information to the STA 103.

[0093] The STA 103 transmits the next divided PPDU 906 to the AP 102 , and the AP 102 transmits a BlockAck frame 907 to the STA 103 .

[0094] The AP 102 acquires the low latency data while receiving the PPDU 906 .

[0095] In response to this, the AP 102 transmits a preemption request frame 908 to the STA 104, and the STA 104 transmits a preemption response frame to the AP 102.

[0096] The preemption response frame of this embodiment may be different from the preemption response frame described in the first embodiment. That is, it may not have a preemption limit field that specifies the length of the PPDU to be transmitted with preemption. The upper limit of the length of the PPDU to be transmitted with preemption may be specified based on the preemption limit field specified in the preemption report frame 901.

[0097] The AP 102 transmits a PPDU 910 including low-latency data to the STA 104, and the STA 104 transmits a BlockAck frame 911 including information on whether the PPDU was received or not to the AP 102.

[0098] Upon receiving the completion of the preemption communication, the STA 103 transmits a PPDU 912 that is the next PPDU after the PPDU 906 to the AP 102, and the AP 102 transmits a BlockAck frame to the STA 103.

[0099] FIG. 11 is a flowchart illustrating the operation of the AP 102 in this embodiment. The flowchart starts by receiving a Preemption report frame from the STA 103 and acquiring the Preemption limit. The acquired value is assumed to be L_prlim.

[0100] The AP 102 receives an RTS frame from the STA 103 and acquires the NAV (S1101). The AP 102 transmits a CTS frame to the STA 103 in response to the RTS frame (S1102).

[0101] When a PPDU is received from the STA 103 in step S1103, a BlockAck frame is transmitted to the STA 103 (S1104).

[0102] If no PPDU is received from the STA 103 in step S1103, the process proceeds to S1105.

[0103] It is determined whether NAV has ended (S1105), and if so, this flowchart ends. If NAV has not ended, the process proceeds to S1106. Then, it is confirmed whether low-latency data to be preemptively transmitted exists in the transmission buffer (S1106). If low-latency data does not exist in the transmission buffer, the process returns to S1103.

[0104] If low-latency data exists, a preemption request frame is transmitted to the STA 104 (S1107).

[0105] If a preemption response frame is received from the STA 104 in S1108, the process proceeds to S1109, and if not, the process proceeds to S1102.

[0106] The PPDU length (denoted as L_ppdu) to be transmitted to the STA 104 is determined so as to be equal to or less than L_prlim (S1109).

[0107] A PPDU is transmitted to the STA 104 (S1110), and the value of L_prlim is updated by subtracting L_ppdu from it (S1111).

[0108] A BlockAck frame is received from the STA 104 (S1112) and the process proceeds to S1102.

[0109] FIG. 12 is a flowchart illustrating the operation of the STA 103 in this embodiment.

[0110] After the STA 103 acquires the TXOP, it transmits a preemption report frame to the AP and STAs that belong to the same BSS (S1201).

[0111] The PPDU to be transmitted to the AP 102 is divided into N pieces (S1202), where N is a predetermined integer equal to or greater than 2. An RTS frame is transmitted to the AP 102 (S1203), and a CTS frame transmitted from the AP 102 is received (S1204).

[0112] Thereafter, the PPDU is transmitted to the AP 102 (S1205), and the BlockAck frame transmitted by the AP 102 is received (S1206).

[0113] If a preemption request frame addressed to another terminal is received in S1207, the process proceeds to S1208, and if not, the process proceeds to S1209.

[0114] In S1208, preemption communication is performed between the AP 102 and the STA 104, and the STA 103 receives the PPDU and BlockAck frame exchanged between the frames, and the process proceeds to S1207.

[0115] If it is determined in S1209 that the segmented PPDU transmitted in S1205 is the Nth segment, the process proceeds to S1210, and if not, the process proceeds to S1205.

[0116] If NAV has not ended in S1210, the process proceeds to S1207, and if it has ended, the process ends this flowchart.

[0117] According to the second embodiment described above, when a PPDU of low latency data is transmitted from the AP 102 to the STA 104 by interrupt during a transmission prohibition time, the transmission time of the low latency data can be limited so as not to exceed the upper limit value (L_prlim). This ensures a certain level of fairness between communications of low latency data and non-low latency data.

[0118] In the second embodiment, a case where a PPDU of low latency data is transmitted from the AP 102 to the STA 104 by interrupt during a transmission prohibition time has been mainly described, but the present invention is not limited to this. That is, the second embodiment is also applicable to a case where a PPDU of low latency data is transmitted from the STA 104 to the AP 102 by interrupt during a transmission prohibition time.

[0119] Furthermore, in the second embodiment, it is assumed that the AP 102 transmits a preemption signal to the STA 104 while the STA 103 has acquired a TXOP and is transmitting a PPDU to the AP 102, but this is not limiting. That is, the second embodiment is also applicable to a case where the STA 104 transmits a preemption signal to the AP 102 while the AP 102 has acquired a TXOP and is transmitting a PPDU to the STA 103. In this case, the AP 102 may transmit a frame corresponding to the preemption report frame to the STA 103 or the STA 104 after acquiring the TXOP. <Third embodiment> 13(a) and 13(b) are sequence diagrams showing an example of processing based on the same premise below. The premise is as follows: AP 102 notifies the connected STAs of information related to preemption communication, including the preemption limit. Then, while AP 102 acquires a TXOP and is transmitting a PPDU to STA 103, STA 104 transmits a preemption signal to AP 102.

[0120] First, the format shown in Fig. 13(a) will be described. AP 102 transmits a beacon frame 1301 to all connected STAs at regular intervals. Beacon frame 1301 includes a Preemption element, an example of which is shown in Fig. 14. The Preemption element includes an Element ID field 1401, a Length field 1402, and an Element ID Extension field 1403. The Preemption element also includes a Preemption allowance field 1404 and a Preemption limit field 1405.

[0121] When the value of the Element ID field is 255 and the value of the Element ID Extension field is 136, this indicates that this element is a preemption element.

[0122] The values ​​in the Element ID field and Element ID Extension field are merely examples, and other combinations that do not overlap with the elements defined in the IEEE 802.11 series standards may be used.

[0123] The Preemption element may have a configuration in which the Element ID field, which is a reserved value in existing standards, is used as the Preemption element and the Element ID Extension field is not included. The bit lengths and meanings of the Preemption allowance field 1404 and the Preemption limit field 1405 are the same as those of the fields with the same names described in the first and second embodiments.

[0124] After acquiring the TXOP, the AP 102 transmits an RTS frame 1302 to the STA 103 and receives a CTS frame 1303 transmitted by the STA 103 .

[0125] The AP 102 divides the PPDU to be transmitted to the STA 103 into an appropriate number of PPDUs and transmits the divided PPDUs in multiple batches.

[0126] The AP 102 transmits a PPDU 1304 to the STA 103 and receives a BlockAck frame 1305 transmitted by the STA 103 .

[0127] The AP 102 again transmits a PPDU 1306 to the STA 103 , and after receiving a BlockAck frame 1307 transmitted by the STA 103 , receives a Preemption request frame 1308 from the STA 104 .

[0128] The AP 102 transmits a preemption response frame 1309 to the STA 104 as a response signal.

[0129] The frame format of the preemption request frame and the preemption response frame may be the frame format described in the first embodiment, or may not have the preemption allowance field and the preemption limit field.

[0130] The STA 104 transmits a PPDU 1310 including low-latency data to the AP 102 as a preemption, and the AP 102 transmits a BlockAck frame 1311 to the STA 104 .

[0131] After the preemption communication is completed, the AP 102 transmits the divided PPDU 1312 to the STA 103, and the STA 103 transmits a BlockAck frame 1313 to the AP 102.

[0132] In the form shown in FIG. 13(b), information regarding preemption is notified by including it in the information exchanged when the AP and the STA connect.

[0133] When the AP 102 and the STA 104 connect, the STA 104 transmits an Association request frame 1314 to the AP 102, and then the AP 102 transmits an Association response frame 1315 to the STA 104. The Association response frame 1315 includes the Preemption element shown in Fig. 14. The Preemption element is the same as that described in the embodiment in which information related to preemption communication is notified by the beacon frame.

[0134] The Association request frame 1314 may include a Preemption element. In this case, the value indicated by the Preemption limit field 1405 may be the requested upper limit value of the total time length of the PPDU in preemption communication transmitted from the STA 104 to the AP 102. Upon receiving the Association request frame 1314, the AP 102 determines or updates the upper limit value of the total time length of the PPDU from the requested value. For example, if the specified value is greater than the requested value from the STA 104, the requested value from the STA 104 may be updated as the upper limit value of the total time length of the PPDU, and if the specified value is smaller than the requested value from the STA 104, the upper limit value of the total time length of the PPDU may not be updated. Note that, although the present embodiment has been described with respect to a configuration in which a Preemption element is included in a beacon frame, an Association Request frame, and an Association Response frame, this is not limiting. For example, the above-described Preemption element may be configured to be included in a Probe Request frame, a Probe Response frame, a Reassociation Request frame, and a Reassociation Response frame. This allows, for example, the STA 104 to notify the upper limit required for the total time length of PPDUs in preemption communication using a Probe Request frame or a Reassociation Request frame, and the AP 102 to notify the upper limit for the total time length of PPDUs in preemption communication using a Probe Response frame or a Reassociation Response frame.

[0135] The processing after the AP 102 acquires the TXOP is the same as the processing described above in the embodiment in which information about preemption communication is notified by beacon frame, and therefore the description thereof will be omitted. Information about preemption communication using an association response frame is notified only at the time of connection. Therefore, by combining this with the information notification by beacon frame described above and the information notification method described in the first and second embodiments, it is also possible to handle updates of associated information.

[0136] According to the third embodiment described above, when a PPDU of low latency data is transmitted from the STA 104 to the AP 102 by interrupt during a transmission prohibition time, the transmission time of the low latency data can be limited so as not to exceed the upper limit value (L_prlim). This ensures a certain level of fairness between communications of low latency data and non-low latency data.

[0137] (Other embodiments) It is also possible to provide a system or device with a storage medium containing program code for software that realizes the above-described functions, and have the computer (CPU, MPU) of the system or device read and execute the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the above-described device.

[0138] Examples of storage media that can be used to supply the program code include flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, ROMs, and DVDs.

[0139] In addition, not only can the above-mentioned functions be realized by the computer executing the program code it has read, but the OS running on the computer can also perform some or all of the actual processing based on the instructions of the program code to realize the above-mentioned functions.

[0140] Furthermore, the program code read from the storage medium may be written to a memory provided on a function expansion board inserted into a computer or a function expansion unit connected to the computer, and a CPU provided on the function expansion board or function expansion unit may then perform some or all of the actual processing based on the instructions of the program code to realize the above-mentioned functions.

[0141] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0142] The following additional notes are provided regarding the above-described embodiments.

[0143] [Appendix 1] A communication device that performs communication in accordance with the IEEE 802.11 standard series, A communication means for communicating a first PPDU (Physical layer (PHY) Protocol Data Unit) with a first other communication device during a period when the communication device has a transmission opportunity (TXOP) for transmitting the PPDU; a notification means for notifying an upper limit value of a transmission opportunity for transmitting a second PPDU when a second other communication device transmits the second PPDU during the period; A communication device comprising: [Appendix 2] A communication device that performs communication in accordance with the IEEE 802.11 standard series, A communication means for communicating a first PPDU (Physical layer (PHY) Protocol Data Unit) with a first other communication device during a period when the first other communication device has a transmission opportunity (TXOP) for transmitting the PPDU; a notification means for notifying an upper limit value of a transmission opportunity for transmitting a second PPDU when a second other communication device transmits the second PPDU during the period; A communication device comprising: [Appendix 3] The notification means notifies the second other communication device of the upper limit value during the period. 3. The communication device according to claim 1 or 2, [Appendix 4] a receiving unit for receiving a first frame indicating a request for transmission of the second PPDU from the second other communication device; When the notification means receives the first frame, the notification means notifies the second other communication device of the upper limit value using a second frame. 4. The communication device according to claim 1, wherein: [Appendix 5] The notification means notifies the upper limit value using a PPDU having a MAC (Media Access Control) header including the upper limit value in an A-Control field. 5. The communication device according to claim 1, wherein: [Appendix 6] The notification means notifies the upper limit value before the period starts. 3. The communication device according to claim 1 or 2, [Appendix 7] The notification means notifies the upper limit value using a beacon frame, a probe response frame, or an association response frame prior to the period in which the device has the transmission opportunity. 10. The communication device according to claim 1, 2, or 6, characterized in that: [Appendix 8] The communication device is an access point device having an access point function, Further comprising a construction means for constructing a network, The first other communication device and the second other communication device are communication devices participating in the network. 8. The communication device according to claim 1, wherein: [Appendix 9] The second other communication device transmits the second PPDU by interrupt communication. 9. The communication device according to claim 1, wherein: [Appendix 10] The second PPDU is a PPDU including data categorized as low latency data. 10. The communication device according to any one of Supplementary Note 1 to Supplementary Note 9, [Appendix 11] The upper limit value indicates a time during which the second other communication device is able to communicate during the period. 11. The communication device according to claim 1, wherein: [Appendix 12] The upper limit value indicates the number of PPDUs that the second other communication device can communicate during the period. 11. The communication device according to claim 1, wherein: [Appendix 13] A communication device that performs communication in accordance with the IEEE 802.11 standard series, a first transmitting means for transmitting a first PPDU to an access point device having an access point function during a period in which the other communication device has a transmission opportunity acquired; a receiving means for receiving a first frame including information indicating an upper limit of a transmission opportunity for transmitting the first PPDU during the period; A communication device comprising: [Appendix 14] The wireless communication device further includes a control unit that controls the first PPDU so that the upper limit value is not exceeded when the first PPDU is transmitted during the period. 14. The communication device according to claim 13, [Appendix 15] and a second transmitting means for transmitting a second frame indicating a request for transmitting the first PPDU when the first PPDU is to be transmitted during the period. 15. The communication device according to claim 13 or 14. [Appendix 16] The first frame is a response frame to the second frame. 16. The communication device according to claim 15, [Appendix 17] The first frame is a Beacon frame or an Association Response frame. 17. The communication device according to any one of Supplementary Note 13 to Supplementary Note 16, [Appendix 18] The first PPDU is a PPDU including data categorized as low latency data. 18. The communication device according to any one of Supplementary Note 13 to Supplementary Note 17, [Explanation of symbols]

[0144] 101 Network 102 AP 103, 104 STA

Claims

1. A communication device that performs communication in accordance with the IEEE 802.11 standard series, a communication means for communicating a first PPDU (Physical layer (PHY) Protocol Data Unit) with a first other communication device during a period when the communication device has a transmission opportunity (TXOP) for transmitting the PPDU; a notification means for notifying an upper limit value of a transmission opportunity for transmitting a second PPDU when a second other communication device transmits the second PPDU during the period; A communication device comprising:

2. A communication device that performs communication in accordance with the IEEE 802.11 standard series, a communication means for communicating a first PPDU (Physical layer (PHY) Protocol Data Unit) with the first other communication device during a period when the first other communication device has a transmission opportunity (TXOP) for transmitting the PPDU; a notification means for notifying an upper limit value of a transmission opportunity for transmitting a second PPDU when a second other communication device transmits the second PPDU during the period; A communication device comprising:

3. The notification means notifies the second other communication device of the upper limit value during the period.

3. The communication device according to claim 1 or 2.

4. a receiving means for receiving a first frame indicating a request for transmission of the second PPDU from the second other communication device; When the notification means receives the first frame, the notification means notifies the second other communication device of the upper limit value using a second frame.

3. The communication device according to claim 1 or 2.

5. The notification means notifies the upper limit value using a PPDU having a MAC (Media Access Control) header including the upper limit value in an A-Control field.

3. The communication device according to claim 1 or 2.

6. The notification means notifies the upper limit value before the period starts.

3. The communication device according to claim 1 or 2.

7. The notification means notifies the upper limit value using a beacon frame, a probe response frame, or an association response frame prior to the period in which the own device has the transmission opportunity.

7. The communication device according to claim 6.

8. The communication device is an access point device having an access point function, Further comprising a construction means for constructing a network, The first other communication device and the second other communication device are communication devices participating in the network.

3. The communication device according to claim 1 or 2.

9. The second other communication device transmits the second PPDU by interrupt communication.

3. The communication device according to claim 1 or 2.

10. The second PPDU is a PPDU containing data categorized as low latency data.

3. The communication device according to claim 1 or 2.

11. The upper limit value indicates the time during which the second other communication device is able to communicate during the period.

3. The communication device according to claim 1 or 2.

12. The upper limit value indicates the number of PPDUs that the second other communication device can communicate during the period.

3. The communication device according to claim 1 or 2.

13. A communication device that performs communication in accordance with the IEEE 802.11 standard series, a first transmitting means for transmitting a first PPDU to an access point device having an access point function during a period in which the other communication device has an acquired transmission opportunity; receiving means for receiving a first frame including information indicating an upper limit of transmission opportunities for transmitting the first PPDU during the period; A communication device comprising:

14. The method further includes a control unit that controls the first PPDU to be transmitted so that the upper limit value is not exceeded when the first PPDU is transmitted during the period.

14. The communication device according to claim 13.

15. and a second transmitting means for transmitting a second frame indicating a request for transmitting the first PPDU when the first PPDU is to be transmitted during the period.

14. The communication device according to claim 13.

16. The first frame is a response frame to the second frame.

16. The communication device according to claim 15.

17. The first frame is a Beacon frame or an Association Response frame.

14. The communication device according to claim 13.

18. The first PPDU is a PPDU containing data categorized as low latency data.

14. The communication device according to claim 13.

19. A method for controlling a communication device that performs communication in accordance with the IEEE 802.11 standard series, comprising: a communication step of communicating a first PPDU (Physical layer (PHY) Protocol Data Unit) with a first other communication device during a period when the communication device has a transmission opportunity (TXOP) for transmitting the PPDU; a notification step of notifying an upper limit value of a transmission opportunity for transmitting a second PPDU when a second other communication device transmits the second PPDU during the period; A control method for a communication device, comprising:

20. A method for controlling a communication device that performs communication in accordance with the IEEE 802.11 standard series, comprising: a communication step of communicating a first PPDU (Physical layer (PHY) Protocol Data Unit) with the first other communication device during a period in which the first other communication device has a transmission opportunity (TXOP) for transmitting the PPDU; a notification step of notifying an upper limit value of a transmission opportunity for transmitting a second PPDU when a second other communication device transmits the second PPDU during the period; A control method for a communication device, comprising:

21. A method for controlling a communication device that performs communication in accordance with the IEEE 802.11 standard series, comprising: a first transmission step of transmitting a first PPDU to an access point device having an access point function during a period in which the other communication device has acquired a transmission opportunity; a receiving step of receiving a first frame including information indicating an upper limit of transmission opportunities for transmitting the first PPDU during the period; A control method for a communication device, comprising:

22. A program for causing a computer to function as the communication device control method according to claim 18.

23. A program for causing a computer to function as the communication device control method according to claim 19.

24. A program for causing a computer to function as the communication device control method according to claim 20.

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